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A081357
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Sublime numbers, numbers for which the number of divisors and the sum of the divisors are both perfect.
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1
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OFFSET
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1,1
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COMMENTS
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a(2) was calculated by K. S. Brown
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REFERENCES
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J.-M. De Koninck, Those Fascinating Numbers, Amer. Math. Soc., 2009. (From N. J. A. Sloane, Aug 28 2009)
J. Griffiths, Lopsided numbers, Mathematical Spectrum, 43 (No. 2, 2010/2011), 53-54. (http://ms.appliedprobability.org/data/files/Articles%2043/43-2-2.pdf)
M. J. Halm, More Sequences, Mpossibilities 83, April 2003
C. A. Pickover, Wonders of Numbers, p. 215
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LINKS
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Table of n, a(n) for n=1..2.
K. S. Brown, Odd Sublime Numbers (posting to sci.math newsgroup)
K. S. Brown, Sublime Numbers
Dean Hickerson, Re: Twelve is special (posting to sci.math newsgroup)
C. A. Pickover, "Wonders of Numbers, Adventures in Mathematics, Mind and Meaning," Zentralblatt review
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EXAMPLE
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a(1) = 12 because 12 + 6 + 4 + 3 + 2 + 1 = 28 is perfect and number of divisors, 6, is also perfect
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CROSSREFS
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Sequence in context: A175906 A144546 A165970 * A127708 A094896 A200065
Adjacent sequences: A081354 A081355 A081356 * A081358 A081359 A081360
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KEYWORD
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hard,nonn,bref,more
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AUTHOR
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Michael Joseph Halm (hierogamous(AT)lycos.com), Apr 20 2003
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EXTENSIONS
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The link to the site "G. Villemin's Almanac of Numbers, membres.lycos.fr/villemingerard/Decompos/Sublime.htm, Nombres Sublimes," has been deleted because Google reports that it contains malware. - N. J. A. Sloane, Mar 27 2011.
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STATUS
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approved
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